The present invention relates broadly to electrical circuit boards, and more particularly to a system for interconnecting such boards. The invention more especially relates to a system wherein the pins in one connector on one side of a circuit board extend through electrically conductive apertures in the circuit board to a socket in a connector on the other side of the circuit board. The resulting assembly of circuit boards and connectors may resemble a "sandwich".
A common problem in interconnecting printed circuit boards is the space required for making the necessary connections. The problem is particularly acute in applications such as guided missiles where equipment must generally be as compact as possible. Unfortunately, the connectors currently used in such applications occupy considerable space between the circuit boards they serve to interconnect. More efficient use of the space in equipment using circuit boards results in smaller equipment which is often critical in applications such as guided missiles. Consequently, the art has sought to reduce the amount of wasted space. It is accordingly a general feature of the present invention to provide a system of interconnecting circuit boards which reduces the space presently required between circuit boards.
The use of pins on connectors which pass through apertures on printed circuit boards is known. For example, U.S. Pat. No. 4,133,592 teaches the use of such connectors to increase the efficiency of connections between printed circuit boards.
Although the use of such connectors is known, there has been no suggestion for using such connectors both to provide the mechanical force necessary to hold the system together and also to provide connections for power and ground circuits. Further, there has been no suggestions for using a split-tip pin which provides a better electrical contact based on (1) the mechanical force it exerts to maintain contact, and (2) its greater surface area of contact.
The invention reduces the wasted space in parallel arrays of printed circuit boards by decreasing the space required for interconnecting the circuit boards. Further, it provides for electrical signal, power, and ground connections between the parallel circuit boards and also provides a mechanical connection using a connector device which is separate from the circuit boards.
The present invention in a broad aspect comprises a system of interconnected printed circuit boards wherein multiple bi-polar assemblies are employed to interconnect two connectors on opposite sides of a printed circuit board with each other and also with the circuit board. In its simplest form an individual assembly comprises an elongated electrical conductor which has a pin at one end and a socket at the other. The assembly is mounted or embedded in a suitable connector board or the like such that the mouth of the socket is generally flush with one surface or side of the connector board, and such that the pin extends beyond the opposite side or surface of the connector board a distance sufficient to pass through an aperture in a circuit board and enter the socket end of a similar assembly in a second connector board. The aperture in the circuit board is, itself, electrically conducting and serves to connect the pin electrically with circuits or the like on the circuit board. At either end of such a system a flexible ribbon conductor with the appropriate pins or sockets connects to the connector for electric signal transmission.
The foregoing assembly is generally preferred for use in transmitting signals between circuit boards and connectors. A modified form of that assembly is preferably employed to make both a mechanical connection and also an electrical connection for transmitting electrical power. The modified form is basically larger and sturdier than the signal form, and includes a split-tip pin.